Improvement in instruments for indicating musical intervals



S. D.- TILLMAN.

Instruments for Indicating Musical Intervals.

7 8 a h m a M d w v .M .L h L w an D t LI R [In A Y v 7 9 S 0 4 m N UNITED STATES PATENT OFFIcE.

snMUEL i). TILLMAN, on JEEsEv orrv, NEW JEEsEv.

ltlPROl/EMENT IN INSTRUMENTS FOR lNDlCATlNG MUSICAL INTERVALS.

Elpecilicatio'n forming part of Letters Patent No. 148,097, dated March 3, 1874 application filed June 27, 1873.

To all whom it may concern.

Be it known that I, SAMUEL T). TILLMAN, of Jersey City, in the county of Hudson and State of New Jersey, have invented a new and Improved Instrumentforlndicating all Musical 1 n tervals and Common Chords; and I do declare that the following is a full and exact description thereof, reference being had to the annexed drawings, making a part of this specification.

The object of my invention is to indicate and measure, by means of musical scales, the diatonic intervals and common chords belonging to any required tonic in the major mode, and at the same time to show, separate and distinct from these, the proper intervals and common chords belonging to the same tonic in the minor mode; also, to make the instrument,embracing fixed and movable scales, in a cheap and effective form.

This invention is an improvement on Letters Patent granted to me on the 8th day of November, 1853. The instrument then patented was designed especially to show the true and tempered intervals of the diatonic scale in the major mode. In practice, however, it was found impracticable to solve all musical problems with that instrument, because it is quite impossible to represent with clearness, on one and the same surface, all the intervals and the common chords belonging to the same tonic in the minor as well as in the major mode. This radical defect I have remedied in my invention hereinafter described. Both inventions are based on the same conception of the progression of pitch represented by the projection of a spiral, each ring of which embraces all the intervals of the diatonic scale. In this arrangement all the octaves of a given sound are found at the points where the same radius-vector intersects the spiral, thus obviatin g the diificulty encountered in measuring intervals on a continuous right line, which requires the addition of the eighth note in order to measure seven intervals. The rings of the spiral represent all the octaves of each sound in the musical series therefore it is only necessary to use one ringof the spiral for illustratin g and measuring musical changes produced by a change in the pitch of the tonic. This ring or single revolution of the spiral is made a true circle for convenience, and on this circle all the intervals within the octave are represented, as herein described.

My invention consists of a ring or annular plate, made of metal or other suitable material, one side of which shows the intervals of the diatonic scale, usually called the fixed scale, (see Figure l in the accompanying drawing,) which are represented by divisions of a circle, and designated by the first seven letters of the alphabet; also, the five intermediate intervals, indicated by flats and sharps, and as made with instruments played by means of keys. These twelve equal parts represent the twelve so-called semitone intervals within the octave. I call them the twelve ascending grades of pitch, one grade being the measure of a semi tone, and two grades being the measure of a tone interval. These twelve grades, or semitone intervals, are numbered like the hours on the dial of a watch: 12 2 4 5 7 9 ll correspond, respectively, to O D E F G A B, representing both the intervals and the sounds of the fixed musical or diatonic scale; and the remaining numbers, 1 3 6 8 10, represent divisions of the five tone intervals, respectively, into semitone intervals, which are designated by either a sharp or a flat added to one of those letters. Within this ring is a disk of metal or other suitable material, which is held in place and arranged so as to rotate freely within the ring. On one side of this disk, as shown in Fig. l, are divisions of a spiral, which measure the intervals of a movable diatonic scale. The length of these seven intervals corresponds to those of the fixed diatonic scale, and is measured in twelfths of the circle. These measurements on the rotating disk are made clear by a combination of inverted curves, and furthcr designated by the solfeggio syllables do re mi fa sol la si. The do nearest the center designates the tonic or key note. A s ciillll do is added above the first to show the octave but this second do is, in fact, the first note of a second series of sounds which, if made, would be corresponding octaves of the seven sounds which form the first series. As the six remaining solfeggio syllables have a fixed relation to the tonic do, it is evident that any change in. the position of do in relation to the fixed scale of the ring would require a correspondin g change in the pitch of other sounds belonging to this tonic. The rotation of the disk shows the changes which may be given to the position of the tonic, and the relations of the movable scale to the fixed scale.

In order to show with distinctness the sounds which produce the common chords belonging to each key, I place within the scale three portions or segments of circles, which measure these major triads; on. each portion are marks in a radial line with those solt'eggio syllables by which the chord is known and distinguished. As major triads are measured by four grades followed by three grades, there can be three different common chords in the diatonie series, namely, as shown in Fig. 1, do mi sol, sol sire, fa la do. All the changes arising from a change of tonic in the major mode, and all the major common chords which can be made, are shown on the face of the ring and disk, as represented in Fig. 1,by altering their relative positions. On the reverse side of the ring and disk, as represented in Fig. 2, are the measurements of intervals required in the minor mode. The measurement of the fixed scale by divisions of a circle on the annular plate or ring into twelve parts is precisely like that shown in Fig. 1. The seven letters are omitted for convenience, but can be added when required. The corresponding numerals on each side of the ring are exactly opposite each other, so that 12 2 -I 5 7 9 1.1 indicate the same sounds in the minor and major modes. ()n the disk, however, as shown in Fig. 2, the divisions marking the intervals are difi'erent. La being taken as the tonic in the minor mode, this syllable has the same position on the circle as do in the major mode; therefore these syllables are exactly opposite each other. From the inner la, (see Fig. 2,) the progression of pitch on the diatonic scale is shown, and la above is the octave of the tonic. In descending the scale, only diatonic intervals are indicated; but in ascending the scale, the last two notes of the scale are commonly raised a semitone. These measurements are shown by inverted curves, and the arrow-heads connected therewith point out the notes used in ascending and descending scale.

To illustrate the use of this instrument, it is only necessary to fix the revolving disk D in a given position so that do on the side showing the intervals in the major mode shall be on one of the sounds indicated on the fixed scale R. All the intervals are then pointed out and on looking at the reverse side, all the intervals used in the minor mode with the same tonic sound are also shown. Figs. 1 and 2 show the two sides of the instrument when do is on C. Thus it is seen that all the diatonic intervals in the major mode are indicated by letters, this being designated as the natural key; yet the same tonic in the minor mode requires the sounds or intervals belonging to the key of E flat; but in ascending the series, 9, or A, may e substituted for S, or A flat, and 11, or B, for 10, or 13 flat. The relative tonics are also shown for each key. For example, Fig. l exhibits the order of the diatonic-seale intervals used in the major mode, U being the tonic of the natural key; if to use the minor mode in the same key, the tonic must be changed from O to A; the relative minor tonic is A, or 9, three grades below 0, or 12. This gives us the rule for finding the relative minor tonic in given key-namely, subtract from the number indicating the tonic in the major mode, three, and the remainder will be the number indicating the minor-mode tonic in the same key. It the major-mode tonic is indicated by a number less than three, then twelve is added to it before the subtraction is made. For example, in the key of five flats, the major-mode tonic is one; consequently the minor-mode tonic is ten. In the same manner the relative major tonic is found by adding three to the number indicating the tonic in the minor mode. As shown in Fig. 2, the tonic in the minor mode is 12; by adding three grades, we find that the relative major tonic is 3, or E Hat.

The common chords in the minor mode are made up of an interval measured by three grades, followed by one of four grades; conse quently there can be formed on the diatonic scale only three regular minor common chords. These are indicated on Fig. 2 by portions of circles and marks, which show these chords to be, first, la do mi; second, re fa la; and, third, mi sol si. There is an imperfect chord or triad made up of two intervals, each measured by three grades; this is shown, by the inner portion of a circle in Fig. 2, to be si re fa, and is the only case where a triad chord embraces six grades or one-half of the whole circle.

Another method of indicating, on the rotating disks, diatonic intervals and chords, is by means of a combination of triangles. The triangle points out the common chord, those with thick lines being the most important. Thus Fig. 3 represents the intervals and chords in the major mode, and Fig. 4c the intervals and chords in the minor mode the triangle formed by dotted lines measures the imperfeet triad. It may be found, in practice, that the use of these triangles, in place of the curves and portions of circles on the rotating disk, will give the student a better idea of harmony. Interesting problems relating to modulation may be solved by the use of the numerals designating the grades or semitones within the octaves.

The ring or annular plate is made of thick copper metal; but, to economize metal, I have invented a mode of stamping out from metal the ring, and using the circular plate cut out of the inside of the ring as the rotating disk. To accomplish this, I form a tongue on the periphery of the disk and along the middle of the plate, of such width as to allow metal to overlap each side without projecting beyond the thickness of the disk; then on the inner and lower edge of the ring, and in the same plane, I form a lip or slight projection, extending inward, and on the inner and upper edge of the ring I form another projection or lip, extending upward or at right angles with the other lip. These lips are made so small as to form, when finished, a diminutive groove on the inside of the ring, in which moves the small tongue already described. After the disk is placed within the ring, so that its tongue rests on the lower lip of the ring, the upper lip is bent from its upright position, so as to have the same direction as the lower lip, thus forming a groove, within which the tongue of the disk will freely rotate. Fig. 5 shows a cross-section of the ring and disk before the upper lip has been bent over the tongue. D is the disk; t t, the tongue resting on the lower lip Z l of ring It; and Z Z is the upper lip ready to be bent over the tongue, so as to prevent the escape of the disk D. In practice, it may be found more convenient to form the tongue 011 the inside of the ring, and the lips for the groove on the outside edges of the disk; this is only a modification of the same device for securingwithin a ring a disk of equal thickness, so that it may move freely therein. This combination of ring and disk having the ap pearance of a medal, I have designated the instrument as a music-medal. The most rapid method of forming the tongue and lips described is by means of pressure in the same dies which form the characters and figures found on the faces of the instrument.

WVhat I claim as new, and desire to secure by Letters Patent, is

1. The combination of the ring R with the inner movable disk D, provided, upon their obverse and reverse faces, with indexes of the major and minor intervals, respectively, the whole forming a music-medal, substantially as and for the purpose described.

2. A medal consisting of the ring R and rotating disk D, such parts being struck up from one piece of metal, substantially as described, with or without the musical indexes hereinbefore mentioned.

SAMUEL D. TILLMAN. Witnesses:

JOHN W. CHAMBERS, DANIEL R. GARDEN. 

